'Dora the Explorer' executive out in Nickelodeon shake-up

Reeling from its spectacular ratings fall, Burbank-based Nickelodeon has pushed out animation chief Brown Johnson, the executive most responsible for creating the network's cartoon sensation "Dora the Explorer."

Johnson is leaving Nickelodeon "to pursue her own creative endeavors," Nickelodeon said in a statement Wednesday. She had served as president of animation for four years, but had been a creative force within the network for two decades.

Johnson was key to Nickelodeon's enormous success during the last decade, guiding "Dora the Explorer" and "Blues Clues," cornerstones of the network's ground-breaking preschool programming. The shows' success, along with the merchandise it spawned, turned Nickelodeon into a cash cow for parent company Viacom Inc.

However, during the last year, Nickelodeon has hemorrhaged young viewers.

The channel's ratings are down nearly 25% compared with last summer in the key demographic of children ages 2 to 11.